Urethane foam is used in architectural building panels, marine floatation, sprayed-on roof materials, and as insulation for the tops of buildings both to prevent leaking and to provide insulation.
The Montreal Protocol, an agreement signed by most of the world's developed nations in 1987, pledges to cut the use of chlorofluorocarbons in the production of urethane foam in half by 1998. It is anticipated that this summer the agreement will be strengthened to totally ban the use of chlorfluorocarbons by the year 2000. In addition, Congress has recently increased taxes on chlorofluorocarbon products. Therefore, alternative sources of foam producing material must be employed. Current replacements for chlorofluorocarbons increase the cost of producing urethane foams. Accordingly, a need currently exists for a low cost method of producing these foams.
The subject invention provides a composition which produces a rigid foam when combined with diphenylmethane diisocyanate in less than stoichiometric amounts. The use of substoichiometric amounts of diphenylmethane diisocyanate is unknown in the prior art, and allows for the production of lower density water blown foam. The subject invention provides a water blown foam having a commercially valuable density of from about 1.5 lb/ft.sup.3 to about 4 lb/ft.sup.3. In summary, the subject invention offers a low cost, environmentally safe alternative to conventional urethane foams.